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Diffstat (limited to 'drivers/i2c/busses/i2c-i801.c')
-rw-r--r--drivers/i2c/busses/i2c-i801.c343
1 files changed, 255 insertions, 88 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index ae2945a5e00..898dcf9c7ad 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -60,10 +60,12 @@
Block process call transaction no
I2C block read transaction yes (doesn't use the block buffer)
Slave mode no
+ Interrupt processing yes
See the file Documentation/i2c/busses/i2c-i801 for details.
*/
+#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
@@ -76,6 +78,7 @@
#include <linux/io.h>
#include <linux/dmi.h>
#include <linux/slab.h>
+#include <linux/wait.h>
/* I801 SMBus address offsets */
#define SMBHSTSTS(p) (0 + (p)->smba)
@@ -91,8 +94,12 @@
/* PCI Address Constants */
#define SMBBAR 4
+#define SMBPCISTS 0x006
#define SMBHSTCFG 0x040
+/* Host status bits for SMBPCISTS */
+#define SMBPCISTS_INTS 0x08
+
/* Host configuration bits for SMBHSTCFG */
#define SMBHSTCFG_HST_EN 1
#define SMBHSTCFG_SMB_SMI_EN 2
@@ -102,12 +109,8 @@
#define SMBAUXCTL_CRC 1
#define SMBAUXCTL_E32B 2
-/* kill bit for SMBHSTCNT */
-#define SMBHSTCNT_KILL 2
-
/* Other settings */
#define MAX_RETRIES 400
-#define ENABLE_INT9 0 /* set to 0x01 to enable - untested */
/* I801 command constants */
#define I801_QUICK 0x00
@@ -117,10 +120,13 @@
#define I801_PROC_CALL 0x10 /* unimplemented */
#define I801_BLOCK_DATA 0x14
#define I801_I2C_BLOCK_DATA 0x18 /* ICH5 and later */
-#define I801_BLOCK_LAST 0x34
-#define I801_I2C_BLOCK_LAST 0x38 /* ICH5 and later */
-#define I801_START 0x40
-#define I801_PEC_EN 0x80 /* ICH3 and later */
+
+/* I801 Host Control register bits */
+#define SMBHSTCNT_INTREN 0x01
+#define SMBHSTCNT_KILL 0x02
+#define SMBHSTCNT_LAST_BYTE 0x20
+#define SMBHSTCNT_START 0x40
+#define SMBHSTCNT_PEC_EN 0x80 /* ICH3 and later */
/* I801 Hosts Status register bits */
#define SMBHSTSTS_BYTE_DONE 0x80
@@ -132,9 +138,11 @@
#define SMBHSTSTS_INTR 0x02
#define SMBHSTSTS_HOST_BUSY 0x01
-#define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_FAILED | \
- SMBHSTSTS_BUS_ERR | SMBHSTSTS_DEV_ERR | \
- SMBHSTSTS_INTR)
+#define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
+ SMBHSTSTS_DEV_ERR)
+
+#define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \
+ STATUS_ERROR_FLAGS)
/* Older devices have their ID defined in <linux/pci_ids.h> */
#define PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS 0x1c22
@@ -154,6 +162,17 @@ struct i801_priv {
unsigned char original_hstcfg;
struct pci_dev *pci_dev;
unsigned int features;
+
+ /* isr processing */
+ wait_queue_head_t waitq;
+ u8 status;
+
+ /* Command state used by isr for byte-by-byte block transactions */
+ u8 cmd;
+ bool is_read;
+ int count;
+ int len;
+ u8 *data;
};
static struct pci_driver i801_driver;
@@ -162,6 +181,7 @@ static struct pci_driver i801_driver;
#define FEATURE_BLOCK_BUFFER (1 << 1)
#define FEATURE_BLOCK_PROC (1 << 2)
#define FEATURE_I2C_BLOCK_READ (1 << 3)
+#define FEATURE_IRQ (1 << 4)
/* Not really a feature, but it's convenient to handle it as such */
#define FEATURE_IDF (1 << 15)
@@ -170,6 +190,7 @@ static const char *i801_feature_names[] = {
"Block buffer",
"Block process call",
"I2C block read",
+ "Interrupt",
};
static unsigned int disable_features;
@@ -205,13 +226,22 @@ static int i801_check_pre(struct i801_priv *priv)
return 0;
}
-/* Convert the status register to an error code, and clear it. */
-static int i801_check_post(struct i801_priv *priv, int status, int timeout)
+/*
+ * Convert the status register to an error code, and clear it.
+ * Note that status only contains the bits we want to clear, not the
+ * actual register value.
+ */
+static int i801_check_post(struct i801_priv *priv, int status)
{
int result = 0;
- /* If the SMBus is still busy, we give up */
- if (timeout) {
+ /*
+ * If the SMBus is still busy, we give up
+ * Note: This timeout condition only happens when using polling
+ * transactions. For interrupt operation, NAK/timeout is indicated by
+ * DEV_ERR.
+ */
+ if (unlikely(status < 0)) {
dev_err(&priv->pci_dev->dev, "Transaction timeout\n");
/* try to stop the current command */
dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n");
@@ -244,64 +274,76 @@ static int i801_check_post(struct i801_priv *priv, int status, int timeout)
dev_dbg(&priv->pci_dev->dev, "Lost arbitration\n");
}
- if (result) {
- /* Clear error flags */
- outb_p(status & STATUS_FLAGS, SMBHSTSTS(priv));
- status = inb_p(SMBHSTSTS(priv)) & STATUS_FLAGS;
- if (status) {
- dev_warn(&priv->pci_dev->dev, "Failed clearing status "
- "flags at end of transaction (%02x)\n",
- status);
- }
- }
+ /* Clear status flags except BYTE_DONE, to be cleared by caller */
+ outb_p(status, SMBHSTSTS(priv));
return result;
}
-static int i801_transaction(struct i801_priv *priv, int xact)
+/* Wait for BUSY being cleared and either INTR or an error flag being set */
+static int i801_wait_intr(struct i801_priv *priv)
{
- int status;
- int result;
int timeout = 0;
-
- result = i801_check_pre(priv);
- if (result < 0)
- return result;
-
- /* the current contents of SMBHSTCNT can be overwritten, since PEC,
- * INTREN, SMBSCMD are passed in xact */
- outb_p(xact | I801_START, SMBHSTCNT(priv));
+ int status;
/* We will always wait for a fraction of a second! */
do {
usleep_range(250, 500);
status = inb_p(SMBHSTSTS(priv));
- } while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_RETRIES));
+ } while (((status & SMBHSTSTS_HOST_BUSY) ||
+ !(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR))) &&
+ (timeout++ < MAX_RETRIES));
- result = i801_check_post(priv, status, timeout > MAX_RETRIES);
- if (result < 0)
- return result;
-
- outb_p(SMBHSTSTS_INTR, SMBHSTSTS(priv));
- return 0;
+ if (timeout > MAX_RETRIES) {
+ dev_dbg(&priv->pci_dev->dev, "INTR Timeout!\n");
+ return -ETIMEDOUT;
+ }
+ return status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR);
}
-/* wait for INTR bit as advised by Intel */
-static void i801_wait_hwpec(struct i801_priv *priv)
+/* Wait for either BYTE_DONE or an error flag being set */
+static int i801_wait_byte_done(struct i801_priv *priv)
{
int timeout = 0;
int status;
+ /* We will always wait for a fraction of a second! */
do {
usleep_range(250, 500);
status = inb_p(SMBHSTSTS(priv));
- } while ((!(status & SMBHSTSTS_INTR))
- && (timeout++ < MAX_RETRIES));
+ } while (!(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_BYTE_DONE)) &&
+ (timeout++ < MAX_RETRIES));
- if (timeout > MAX_RETRIES)
- dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n");
+ if (timeout > MAX_RETRIES) {
+ dev_dbg(&priv->pci_dev->dev, "BYTE_DONE Timeout!\n");
+ return -ETIMEDOUT;
+ }
+ return status & STATUS_ERROR_FLAGS;
+}
- outb_p(status, SMBHSTSTS(priv));
+static int i801_transaction(struct i801_priv *priv, int xact)
+{
+ int status;
+ int result;
+
+ result = i801_check_pre(priv);
+ if (result < 0)
+ return result;
+
+ if (priv->features & FEATURE_IRQ) {
+ outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
+ SMBHSTCNT(priv));
+ wait_event(priv->waitq, (status = priv->status));
+ priv->status = 0;
+ return i801_check_post(priv, status);
+ }
+
+ /* the current contents of SMBHSTCNT can be overwritten, since PEC,
+ * SMBSCMD are passed in xact */
+ outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv));
+
+ status = i801_wait_intr(priv);
+ return i801_check_post(priv, status);
}
static int i801_block_transaction_by_block(struct i801_priv *priv,
@@ -321,8 +363,8 @@ static int i801_block_transaction_by_block(struct i801_priv *priv,
outb_p(data->block[i+1], SMBBLKDAT(priv));
}
- status = i801_transaction(priv, I801_BLOCK_DATA | ENABLE_INT9 |
- I801_PEC_EN * hwpec);
+ status = i801_transaction(priv, I801_BLOCK_DATA |
+ (hwpec ? SMBHSTCNT_PEC_EN : 0));
if (status)
return status;
@@ -338,6 +380,98 @@ static int i801_block_transaction_by_block(struct i801_priv *priv,
return 0;
}
+static void i801_isr_byte_done(struct i801_priv *priv)
+{
+ if (priv->is_read) {
+ /* For SMBus block reads, length is received with first byte */
+ if (((priv->cmd & 0x1c) == I801_BLOCK_DATA) &&
+ (priv->count == 0)) {
+ priv->len = inb_p(SMBHSTDAT0(priv));
+ if (priv->len < 1 || priv->len > I2C_SMBUS_BLOCK_MAX) {
+ dev_err(&priv->pci_dev->dev,
+ "Illegal SMBus block read size %d\n",
+ priv->len);
+ /* FIXME: Recover */
+ priv->len = I2C_SMBUS_BLOCK_MAX;
+ } else {
+ dev_dbg(&priv->pci_dev->dev,
+ "SMBus block read size is %d\n",
+ priv->len);
+ }
+ priv->data[-1] = priv->len;
+ }
+
+ /* Read next byte */
+ if (priv->count < priv->len)
+ priv->data[priv->count++] = inb(SMBBLKDAT(priv));
+ else
+ dev_dbg(&priv->pci_dev->dev,
+ "Discarding extra byte on block read\n");
+
+ /* Set LAST_BYTE for last byte of read transaction */
+ if (priv->count == priv->len - 1)
+ outb_p(priv->cmd | SMBHSTCNT_LAST_BYTE,
+ SMBHSTCNT(priv));
+ } else if (priv->count < priv->len - 1) {
+ /* Write next byte, except for IRQ after last byte */
+ outb_p(priv->data[++priv->count], SMBBLKDAT(priv));
+ }
+
+ /* Clear BYTE_DONE to continue with next byte */
+ outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
+}
+
+/*
+ * There are two kinds of interrupts:
+ *
+ * 1) i801 signals transaction completion with one of these interrupts:
+ * INTR - Success
+ * DEV_ERR - Invalid command, NAK or communication timeout
+ * BUS_ERR - SMI# transaction collision
+ * FAILED - transaction was canceled due to a KILL request
+ * When any of these occur, update ->status and wake up the waitq.
+ * ->status must be cleared before kicking off the next transaction.
+ *
+ * 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
+ * occurs for each byte of a byte-by-byte to prepare the next byte.
+ */
+static irqreturn_t i801_isr(int irq, void *dev_id)
+{
+ struct i801_priv *priv = dev_id;
+ u16 pcists;
+ u8 status;
+
+ /* Confirm this is our interrupt */
+ pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists);
+ if (!(pcists & SMBPCISTS_INTS))
+ return IRQ_NONE;
+
+ status = inb_p(SMBHSTSTS(priv));
+ if (status != 0x42)
+ dev_dbg(&priv->pci_dev->dev, "irq: status = %02x\n", status);
+
+ if (status & SMBHSTSTS_BYTE_DONE)
+ i801_isr_byte_done(priv);
+
+ /*
+ * Clear irq sources and report transaction result.
+ * ->status must be cleared before the next transaction is started.
+ */
+ status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS;
+ if (status) {
+ outb_p(status, SMBHSTSTS(priv));
+ priv->status |= status;
+ wake_up(&priv->waitq);
+ }
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * For "byte-by-byte" block transactions:
+ * I2C write uses cmd=I801_BLOCK_DATA, I2C_EN=1
+ * I2C read uses cmd=I801_I2C_BLOCK_DATA
+ */
static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
union i2c_smbus_data *data,
char read_write, int command,
@@ -347,7 +481,6 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
int smbcmd;
int status;
int result;
- int timeout;
result = i801_check_pre(priv);
if (result < 0)
@@ -360,36 +493,39 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
outb_p(data->block[1], SMBBLKDAT(priv));
}
+ if (command == I2C_SMBUS_I2C_BLOCK_DATA &&
+ read_write == I2C_SMBUS_READ)
+ smbcmd = I801_I2C_BLOCK_DATA;
+ else
+ smbcmd = I801_BLOCK_DATA;
+
+ if (priv->features & FEATURE_IRQ) {
+ priv->is_read = (read_write == I2C_SMBUS_READ);
+ if (len == 1 && priv->is_read)
+ smbcmd |= SMBHSTCNT_LAST_BYTE;
+ priv->cmd = smbcmd | SMBHSTCNT_INTREN;
+ priv->len = len;
+ priv->count = 0;
+ priv->data = &data->block[1];
+
+ outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv));
+ wait_event(priv->waitq, (status = priv->status));
+ priv->status = 0;
+ return i801_check_post(priv, status);
+ }
+
for (i = 1; i <= len; i++) {
- if (i == len && read_write == I2C_SMBUS_READ) {
- if (command == I2C_SMBUS_I2C_BLOCK_DATA)
- smbcmd = I801_I2C_BLOCK_LAST;
- else
- smbcmd = I801_BLOCK_LAST;
- } else {
- if (command == I2C_SMBUS_I2C_BLOCK_DATA
- && read_write == I2C_SMBUS_READ)
- smbcmd = I801_I2C_BLOCK_DATA;
- else
- smbcmd = I801_BLOCK_DATA;
- }
- outb_p(smbcmd | ENABLE_INT9, SMBHSTCNT(priv));
+ if (i == len && read_write == I2C_SMBUS_READ)
+ smbcmd |= SMBHSTCNT_LAST_BYTE;
+ outb_p(smbcmd, SMBHSTCNT(priv));
if (i == 1)
- outb_p(inb(SMBHSTCNT(priv)) | I801_START,
+ outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START,
SMBHSTCNT(priv));
- /* We will always wait for a fraction of a second! */
- timeout = 0;
- do {
- usleep_range(250, 500);
- status = inb_p(SMBHSTSTS(priv));
- } while ((!(status & SMBHSTSTS_BYTE_DONE))
- && (timeout++ < MAX_RETRIES));
-
- result = i801_check_post(priv, status, timeout > MAX_RETRIES);
- if (result < 0)
- return result;
+ status = i801_wait_byte_done(priv);
+ if (status)
+ goto exit;
if (i == 1 && read_write == I2C_SMBUS_READ
&& command != I2C_SMBUS_I2C_BLOCK_DATA) {
@@ -416,10 +552,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
outb_p(data->block[i+1], SMBBLKDAT(priv));
/* signals SMBBLKDAT ready */
- outb_p(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR, SMBHSTSTS(priv));
+ outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
}
- return 0;
+ status = i801_wait_intr(priv);
+exit:
+ return i801_check_post(priv, status);
}
static int i801_set_block_buffer_mode(struct i801_priv *priv)
@@ -474,9 +612,6 @@ static int i801_block_transaction(struct i801_priv *priv,
read_write,
command, hwpec);
- if (result == 0 && hwpec)
- i801_wait_hwpec(priv);
-
if (command == I2C_SMBUS_I2C_BLOCK_DATA
&& read_write == I2C_SMBUS_WRITE) {
/* restore saved configuration register value */
@@ -564,7 +699,7 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
ret = i801_block_transaction(priv, data, read_write, size,
hwpec);
else
- ret = i801_transaction(priv, xact | ENABLE_INT9);
+ ret = i801_transaction(priv, xact);
/* Some BIOSes don't like it when PEC is enabled at reboot or resume
time, so we forcibly disable it after every transaction. Turn off
@@ -799,6 +934,16 @@ static int __devinit i801_probe(struct pci_dev *dev,
break;
}
+ /* IRQ processing tested on CougarPoint PCH, ICH5, ICH7-M and ICH10 */
+ if (dev->device == PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS ||
+ dev->device == PCI_DEVICE_ID_INTEL_82801EB_3 ||
+ dev->device == PCI_DEVICE_ID_INTEL_ICH7_17 ||
+ dev->device == PCI_DEVICE_ID_INTEL_ICH8_5 ||
+ dev->device == PCI_DEVICE_ID_INTEL_ICH9_6 ||
+ dev->device == PCI_DEVICE_ID_INTEL_ICH10_4 ||
+ dev->device == PCI_DEVICE_ID_INTEL_ICH10_5)
+ priv->features |= FEATURE_IRQ;
+
/* Disable features on user request */
for (i = 0; i < ARRAY_SIZE(i801_feature_names); i++) {
if (priv->features & disable_features & (1 << i))
@@ -846,16 +991,30 @@ static int __devinit i801_probe(struct pci_dev *dev,
}
pci_write_config_byte(priv->pci_dev, SMBHSTCFG, temp);
- if (temp & SMBHSTCFG_SMB_SMI_EN)
+ if (temp & SMBHSTCFG_SMB_SMI_EN) {
dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n");
- else
- dev_dbg(&dev->dev, "SMBus using PCI Interrupt\n");
+ /* Disable SMBus interrupt feature if SMBus using SMI# */
+ priv->features &= ~FEATURE_IRQ;
+ }
/* Clear special mode bits */
if (priv->features & (FEATURE_SMBUS_PEC | FEATURE_BLOCK_BUFFER))
outb_p(inb_p(SMBAUXCTL(priv)) &
~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv));
+ if (priv->features & FEATURE_IRQ) {
+ init_waitqueue_head(&priv->waitq);
+
+ err = request_irq(dev->irq, i801_isr, IRQF_SHARED,
+ i801_driver.name, priv);
+ if (err) {
+ dev_err(&dev->dev, "Failed to allocate irq %d: %d\n",
+ dev->irq, err);
+ goto exit_release;
+ }
+ dev_info(&dev->dev, "SMBus using PCI Interrupt\n");
+ }
+
/* set up the sysfs linkage to our parent device */
priv->adapter.dev.parent = &dev->dev;
@@ -867,14 +1026,18 @@ static int __devinit i801_probe(struct pci_dev *dev,
err = i2c_add_adapter(&priv->adapter);
if (err) {
dev_err(&dev->dev, "Failed to add SMBus adapter\n");
- goto exit_release;
+ goto exit_free_irq;
}
i801_probe_optional_slaves(priv);
pci_set_drvdata(dev, priv);
+
return 0;
+exit_free_irq:
+ if (priv->features & FEATURE_IRQ)
+ free_irq(dev->irq, priv);
exit_release:
pci_release_region(dev, SMBBAR);
exit:
@@ -888,7 +1051,11 @@ static void __devexit i801_remove(struct pci_dev *dev)
i2c_del_adapter(&priv->adapter);
pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
+
+ if (priv->features & FEATURE_IRQ)
+ free_irq(dev->irq, priv);
pci_release_region(dev, SMBBAR);
+
pci_set_drvdata(dev, NULL);
kfree(priv);
/*